Мoбилен оператор ; Mobile operator

using System;

namespace tESt
{
    class Program
    {
        static void Main(string[] args)
        {

            var lenghtContract = Console.ReadLine().ToLower(); // “one”, или “two”
            var typeContract = Console.ReadLine().ToLower();   // Small”,  “Middle”, “Large”или “ExtraLarge”;
            var internet = Console.ReadLine().ToLower();       // “yes”, или “no” интернет
            var months = int.Parse(Console.ReadLine());  // месеци за плащане

            double totalSum = 0;


            if (lenghtContract == "one")
            {
                if (typeContract == "small")
                {
                    totalSum = 9.98;
                }
                else if (typeContract == "middle")
                {
                    totalSum = 18.99;
                }
                else if (typeContract == "large")
                {
                    totalSum = 25.98;
                }
                else if (typeContract == "extralarge")
                {
                    totalSum = 35.99;
                }
            }
            else if (lenghtContract == "two")
            {
                if (typeContract == "small")
                {
                    totalSum = 8.58;
                }
                else if (typeContract == "middle")
                {
                    totalSum = 17.09;
                }
                else if (typeContract == "large")
                {
                    totalSum = 23.59;
                }
                else if (typeContract == "extralarge")
                {
                    totalSum = 31.79;
                }
            }



            if (internet == "yes")
            {
                if (totalSum <= 10)
                {
                    totalSum = totalSum + 5.50;
                }
                else if (totalSum <= 30)
                {
                    totalSum = totalSum + 4.35;
                }
                else if (totalSum > 30)
                {
                    totalSum = totalSum + 3.85;
                }
                if (lenghtContract == "two")
                {
                    totalSum = totalSum * 0.9625;
                }
            }
            else
            {
                if(lenghtContract == "two")
                {
                    totalSum = totalSum * 0.9625;
                }
            }

            var finalSum = totalSum * months;
            Console.WriteLine($"{finalSum:f2} lv.");
        }
    }
}